1. Field of the Invention
The present invention relates to electrical connectors, and particularly to electrical connectors that are attached to a circuit substrate by use of solder balls attached to contacts.
2. Description of Related Art
As the size of electronic devices in which circuit boards are installed decreases, the density of electrical connectors positioned on the board must increase so as to meet the requirements. Consequently, the electrical connectors with numerous contacts extending therefrom should be mounted on the board in such a manner so as to occupy a minimal area of board real estate.
It is well known that surface mount technology (SMT) is widely used for connection of the contacts of the electrical connector to the printed circuit board on which the connector is seated. Conductive pads on the printed circuit board can be closely spaced, thereby allowing more contacts to be mounted in the same area of the board. Subsequently, the electrical connectors are developed to have solder balls attached on solder tails of the contacts, i.e., ball grid array (BGA) connectors for ensuring a reliable electrical connection between the connectors and the printed circuit board.
U.S. Pat. No. 5,997,317 issued to Pei et al. on Dec. 7, 1999 discloses a typical ball grid array (BGA) connector. This ball grid array connector comprises an insulating housing defining a plurality of passageways between a mating face and an opposite mounting face, and a plurality of contacts received in the passageways of the housing. Each contact includes a mating portion and a dish-shaped solder portion substantially perpendicular to the mating portion. After the contacts are installed in the insulating housing, a solder ball is attached to a bottom of the dish-shaped solder portion. The solder ball is then soldered on a conductive pad of a printed circuit board for mounting the connector on the printed circuit board. However, the contacts are difficult to make due to their complicated shape, thereby increasing the manufacturing cost.
U.S. Pat. No. 6,139,336 issued to Olson on Oct. 31, 2000 discloses a ball grid array connector of another type. The ball grid array connector comprises an insulating housing defining a plurality of passageways each having a recess in a mounting surface thereof, a plurality of contacts received in the passageways and a solder ball fused to a tail end of each contact for connection of the connector to a circuit substrate. The tail end of the contact terminates in the recess that facilitates the attachment of the solder ball to the end of the contact.
The ball grid array connectors, which have the recesses in the mounting surface of the housing for positioning the solder balls as disclosed in the ""336 patent, can be further referred to U.S. Pat. Nos. 6,024,584, 6,079,991, 6,093,035, 6,164,983, 6,325,644 and 6,042,389.
However, the structure of the housing becomes complicated due to the recesses in the mounting surface, thereby increasing the difficulty of manufacturing the housing.
Hence, the present invention aims to provide a ball grid array connector of new type.
Accordingly, it is an object of the present invention to provide a ball grid array connector facilitating attachment of fusible elements which are to be soldered to a circuit substrate on which the connector is mounted.
In order to achieve the object set forth, a ball grid array connector in accordance with the present invention comprises a dielectric housing having a mounting surface and a plurality of passageways extending through the mounting surface and a plurality of contacts received in the passageways of the housing. Each passageway receives dual contacts therein. The dual contacts have mating portions for engagement with a complementary connector and angled tail portions extending opposing to each other to form a recess therebetween. A plurality of fusible elements each is positioned in the recess of the corresponding dual contacts and attached to the tail portions of the corresponding dual contacts for soldering to a circuit substrate on which the connector is seated.
Other objects, advantages and novel features of the invention will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings.